Removable small IC memories, called “memory cards,” are known, each to be removably inserted into a data-recording and/or reproducing apparatus and used as a data storage medium that has a NAND-type flash memory. Such an IC memory is disclosed in Jpn. Pat. Appln. Laid-Open Publication No. 10-340575. The memory card disclosed in this publication can store various types of digital data, such as still-picture data, moving-picture data, audio data and music data. It is used as an external storage medium in host apparatuses such as mobile information terminals, desktop computers, notebook computers, mobile telephones, audio apparatuses, household appliance and the like.
In recent years, the development of NAND-type flash memories has progressed, rapidly increasing the storage capacity of the flash memory of this type. Hence, the storage capacity of each memory card incorporating the NAND-type flash memory has proportionally increased.
The memory card has its storage capacity limited in accordance with the file system employed for it. If the memory card incorporates a flash memory that has a storage capacity larger than its storage capacity thus limited, part of the storage capacity of the flash memory will be wasted. To use the flash memory to its full storage capacity, the memory card needs to use a new file system.
To use a memory card for which a new file system is used, the host apparatus must have its operation system changed, in most cases. A complex process needs to be performed to change the operation system of the host apparatus. This requires much labor and high cost.
If a memory card is to be provided, which has a storage capacity exceeding the capacity manageable by the conventional file system, it should be used in a host apparatus, without the necessity of changing the operating system of the host apparatus.
In managing the data recorded in a memory card, it may be convenient in some cases if the storage area of the memory card is divided into several regions and if each storage region is recognized as an independent device. For example, it is very convenient for the user if his work-related information and his private information are stored in two different devices (two storage regions), respectively.
As a memory card thus devised, there is known a switch-changeover memory card incorporating a plurality of flash memories that can be switched from one to another by operating an external changeover switch. Jpn. Pat. Appln. Laid-Open Publication No. 5-233439 discloses a memory card of this type. The storage regions of the switch-changeover memory card can be recognized as independent devices to the host apparatus that incorporates this memory card. The switch-changeover memory card can have a total storage capacity, or a single-package storage capacity, exceeding the upper limit that the conventional file system can manage.
Assume that the conventional switch-changeover memory card has been incorporated into the host apparatus. Then, the host apparatus cannot recognize the devices (i.e., the storage regions of the switch-changeover memory card) when the external switch is operated. In the worst case, the data stored is destroyed.
As long as the conventional switch-changeover memory card remains held in the host apparatus, the user cannot determine which flash memory is selected and used at present. The user must remove the memory card from the host apparatus and must check the switch in order to determine which storage region of the memory card is selected.